Substitution of fluorine for hydrogen in polymers and coatings is often desirable to impart useful properties such as lower surface energy which is necessary for stain resistance. Typically, the incorporation of fluorine into polymers and coatings has been made by copolymerizing (meth)acrylate monomers derived from (meth)acrylic acid and highly fluorinated alcohols. These fluorinated (meth)acrylate monomers are available commercially from several sources. Despite their general availability, however, (meth)acrylates often polymerize at slow rates and provide polymers which possess inadequate thermal and hydrolytic stabilities.
Fluorinated (meth)acrylamide monomers have been described in several patents. U.S. Pat. Nos. 2,743,297; 2,957,914; and 3,997,604 disclose fluorinated (meth)acrylamide monomers prepared by the reaction of fluorinated secondary or primary amines and (meth)acryloyl chloride; a complication in the synthesis is removal of the hydrogen chloride by-product. U.S. Pat. No. 3,475,434 teaches the reaction of a stoichiometric excess (about 300 percent) of a short chain diamine with a perfluorinated acylating agent, isolation and purification of the monoperfluoroamide, and (meth)acryloylation of the remaining amine function with the appropriate acid chloride; here again hydrogen chloride is a troublesome by-product, and the complexity of the synthesis is self-evident. U.S. Pat. No. 3,655,732 teaches a multi-step synthesis of fluorinated acrylamides which possess a heteroatom, typically sulfur, as part of a five atom linking group between the acrylamide and perfluorinated moieties.
2 Alkenyl azlactones are known to react with certain nucleophiles such as primary amines and alcohols to afford (meth)acrylamide-functional products. The interested reader is referred to our recent review article entitled "Polyazlactones" which is contained in the Encyclopedia of Polymer Science and Engineering, Volume 11, 2nd edition, 1988. The reaction product of 2-vinyl-4,4-dimethylazlactone and 2,2,2-trifluoroethylamine is a high melting solid (m.p. 135.degree.-136.degree. C.), having been reported by L.D. Taylor, et al., J. Polymer Sci. Polymer Lett., 7, 597 (1969). U.S. Pat. No. 4,447,493 discloses the reaction product of a 2-alkenyl azlactone and poly(perfluorooxyalkylene) polyols, but these materials contain main chain heteroatoms (oxygen) and often yield highly colored reaction products which can be undesirable; additionally, the highly oxygenated, relatively high molecular weight reaction products tend to be less compatible with other necessary additives such as monomers, crosslinking agents, and photoinitiators.